chore: make CASTF unit test match

[jonathanpwang]

#1206 (comment)

It doesn't matter for unit test because unit tester doesn't check against program code, but fixing the unit test so the usage matches how it should be used in practice.

We will more thoroughly address a better handling of offsets soon.

[jonathanpwang]

cc @lispc

[jonathanpwang]

closing to address in general offset cleanup because other tests just set offset=0

[github-actions]

group	app.proof_time_ms	app.cycles	app.cells_used	leaf.proof_time_ms	leaf.cycles	leaf.cells_used
verify_fibair	(+332 [+9.5%]) 3,817	(+35063 [+4.9%]) 746,347	(+4502019 [+17.6%]) 30,012,964	-	-	-
fibonacci_program	(+9 [+0.1%]) 6,076	1,500,137	51,505,102	-	-	-
regex_program	(+160 [+0.8%]) 19,156	4,190,904	165,028,173	-	-	-
ecrecover_program	(-18 [-0.7%]) 2,576	285,401	15,092,297	-	-	-

Commit: 865af5a

Benchmark Workflow